Huawei Quidway NetEngine80E Configuration Manual page 525

HUAWEI NetEngine80E/40E Router
Configuration Guide - IP Routing
IS-IS TE
IS-IS TE supports MPLS to set up and maintain the label switched paths (LSPs).
When establishing constraint-based routed (CR) LSPs, MPLS needs to learn the traffic attributes
of all the links in the local area. CR-LSPs can acquire the TE information of the links using IS-
IS.
Administrative Tag
The use of administrative tags simplifies management. Administrative tags can advertise IP
address prefixes in the IS-IS area to control routes. The administrative tag carries the
administrative information about an IP address prefix. It is used to control the routes of different
levels and routes imported from different areas, various routing protocols, multiple IS-IS
instances running on a router, and carrying of tags.
Each administrative tag is associated with certain attributes. If the prefix of the reachable IP
address to be advertised by IS-IS has this attribute, IS-IS adds the administrative tag to the
reachability TLV in the prefix. In this manner, the tag is advertised throughout the entire IS-IS
area.
LSP Fragment Extension
When more information is carried in an LSP to be advertised by IS-IS, IS-IS advertises multiple
LSP fragments. Each LSP fragment is identified by the LSP identifier field of an LSP. The LSP
identifier field is 1 byte long. Therefore, the maximum number of fragments that can be generated
by an IS-IS device is 256.
The IS-IS fragment extension feature allows an IS-IS device to generate more LSP fragments.
To implement this feature, you can use the network manager to configure additional system IDs
for the router. Each system ID represents a virtual system, which can generate 256 LSP
fragments. With more additional system IDs (up to 50 virtual systems), an IS-IS device can
generate a maximum of 13056 LSP fragments.
l
Issue 02 (2014-09-30)
NOTE
For details about IS-IS TE, see the HUAWEI NetEngine80E/40E Router Configuration Guide-MPLS.
All the other LSPs referred to in this chapter are link state protocol data units. Differentiate the two
acronyms.
Related terms are as follows:
– Originating system
In this document, the originating system is the router that actually runs the IS-IS
protocol, and each IS-IS process is regraded as multiple virtual routers to generate LSP
fragments.
– Normal system ID
It is the system ID of the originating system.
– Additional System-ID
An additional system ID, assigned by the network administrator, represents a virtual
system. Each virtual system is allowed to generate up to 256 extended LSP fragments.
Like a normal system ID, an additional system ID must be unique in a routing domain.
– Virtual system
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
7 IS-IS Configuration
500